DefaultTrackNameProvider.java

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package androidx.media3.ui;

import android.content.res.Resources;
import android.text.TextUtils;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.Format;
import androidx.media3.common.MimeTypes;
import androidx.media3.common.util.Assertions;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import java.util.Locale;

/** A default {@link TrackNameProvider}. */
@UnstableApi
public class DefaultTrackNameProvider implements TrackNameProvider {

  private final Resources resources;

  /**
   * @param resources Resources from which to obtain strings.
   */
  public DefaultTrackNameProvider(Resources resources) {
    this.resources = Assertions.checkNotNull(resources);
  }

  @Override
  public String getTrackName(Format format) {
    String trackName;
    int trackType = inferPrimaryTrackType(format);
    if (trackType == C.TRACK_TYPE_VIDEO) {
      trackName =
          joinWithSeparator(
              buildRoleString(format), buildResolutionString(format), buildBitrateString(format));
    } else if (trackType == C.TRACK_TYPE_AUDIO) {
      trackName =
          joinWithSeparator(
              buildLanguageOrLabelString(format),
              buildAudioChannelString(format),
              buildBitrateString(format));
    } else {
      trackName = buildLanguageOrLabelString(format);
    }
    if (trackName.length() != 0) {
      return trackName;
    }
    @Nullable String language = format.language;
    return (language == null || language.trim().isEmpty())
        ? resources.getString(R.string.exo_track_unknown)
        : resources.getString(R.string.exo_track_unknown_name, language);
  }

  private String buildResolutionString(Format format) {
    int width = format.width;
    int height = format.height;
    return width == Format.NO_VALUE || height == Format.NO_VALUE
        ? ""
        : resources.getString(R.string.exo_track_resolution, width, height);
  }

  private String buildBitrateString(Format format) {
    int bitrate = format.bitrate;
    return bitrate == Format.NO_VALUE
        ? ""
        : resources.getString(R.string.exo_track_bitrate, bitrate / 1000000f);
  }

  private String buildAudioChannelString(Format format) {
    int channelCount = format.channelCount;
    if (channelCount == Format.NO_VALUE || channelCount < 1) {
      return "";
    }
    switch (channelCount) {
      case 1:
        return resources.getString(R.string.exo_track_mono);
      case 2:
        return resources.getString(R.string.exo_track_stereo);
      case 6:
      case 7:
        return resources.getString(R.string.exo_track_surround_5_point_1);
      case 8:
        return resources.getString(R.string.exo_track_surround_7_point_1);
      default:
        return resources.getString(R.string.exo_track_surround);
    }
  }

  private String buildLanguageOrLabelString(Format format) {
    String languageAndRole =
        joinWithSeparator(buildLanguageString(format), buildRoleString(format));
    return TextUtils.isEmpty(languageAndRole) ? buildLabelString(format) : languageAndRole;
  }

  private String buildLabelString(Format format) {
    return TextUtils.isEmpty(format.label) ? "" : format.label;
  }

  private String buildLanguageString(Format format) {
    @Nullable String language = format.language;
    if (TextUtils.isEmpty(language) || C.LANGUAGE_UNDETERMINED.equals(language)) {
      return "";
    }
    Locale languageLocale =
        Util.SDK_INT >= 21 ? Locale.forLanguageTag(language) : new Locale(language);
    Locale displayLocale = Util.getDefaultDisplayLocale();
    String languageName = languageLocale.getDisplayName(displayLocale);
    if (TextUtils.isEmpty(languageName)) {
      return "";
    }
    try {
      // Capitalize the first letter. See: https://github.com/google/ExoPlayer/issues/9452.
      int firstCodePointLength = languageName.offsetByCodePoints(0, 1);
      return languageName.substring(0, firstCodePointLength).toUpperCase(displayLocale)
          + languageName.substring(firstCodePointLength);
    } catch (IndexOutOfBoundsException e) {
      // Should never happen, but return the unmodified language name if it does.
      return languageName;
    }
  }

  private String buildRoleString(Format format) {
    String roles = "";
    if ((format.roleFlags & C.ROLE_FLAG_ALTERNATE) != 0) {
      roles = resources.getString(R.string.exo_track_role_alternate);
    }
    if ((format.roleFlags & C.ROLE_FLAG_SUPPLEMENTARY) != 0) {
      roles = joinWithSeparator(roles, resources.getString(R.string.exo_track_role_supplementary));
    }
    if ((format.roleFlags & C.ROLE_FLAG_COMMENTARY) != 0) {
      roles = joinWithSeparator(roles, resources.getString(R.string.exo_track_role_commentary));
    }
    if ((format.roleFlags & (C.ROLE_FLAG_CAPTION | C.ROLE_FLAG_DESCRIBES_MUSIC_AND_SOUND)) != 0) {
      roles =
          joinWithSeparator(roles, resources.getString(R.string.exo_track_role_closed_captions));
    }
    return roles;
  }

  private String joinWithSeparator(String... items) {
    String itemList = "";
    for (String item : items) {
      if (item.length() > 0) {
        if (TextUtils.isEmpty(itemList)) {
          itemList = item;
        } else {
          itemList = resources.getString(R.string.exo_item_list, itemList, item);
        }
      }
    }
    return itemList;
  }

  private static int inferPrimaryTrackType(Format format) {
    int trackType = MimeTypes.getTrackType(format.sampleMimeType);
    if (trackType != C.TRACK_TYPE_UNKNOWN) {
      return trackType;
    }
    if (MimeTypes.getVideoMediaMimeType(format.codecs) != null) {
      return C.TRACK_TYPE_VIDEO;
    }
    if (MimeTypes.getAudioMediaMimeType(format.codecs) != null) {
      return C.TRACK_TYPE_AUDIO;
    }
    if (format.width != Format.NO_VALUE || format.height != Format.NO_VALUE) {
      return C.TRACK_TYPE_VIDEO;
    }
    if (format.channelCount != Format.NO_VALUE || format.sampleRate != Format.NO_VALUE) {
      return C.TRACK_TYPE_AUDIO;
    }
    return C.TRACK_TYPE_UNKNOWN;
  }
}